1. Field of the Invention
The present invention relates generally to a speech recognition system for an automotive vehicle, and more particularly to a speech recognition system by which a plurality of predetermined spoken instructions are selectively recognized according to vehicle-travelling conditions.
2. Description of the Prior Art
Conventionally, there is well known a speech recognizer which can activate various actuators in response to human spoken instructions. When this speech recognizer is mounted on a vehicle, the headlight, for instance, can be turned on or off by the driver's spoken instruction such as "Headlight on" or "Headlight off". Such a speech recognizer usually can recognize various spoken instructions in order to control various actuators; however, there are some problems involved in applying this system to an automotive vehicle. In the case where the speech recognizer is so designed as to activate a dooropening mechanism in response to the driver's spoken instruction, for example, "Door open", if some passengers have a conversation including the phrase "Door open" while the vehicle is travelling, a dangerous situation may occur in that all the vehicle doors will open while the vehicle is travelling at high speed. Therefore, generally, there is provided a recognition switch which allows spoken instructions to be inputted to the speech recognizer only while this switch is depressed; even so, from the standpoint of safety spoken phrase such as "Door open" should not be recognized by the speech recognizer at all while the vehicle is travelling. On the other hand, there are some spoken instructions, for instance, such as "Headlight high-beam" which are usually used only while the vehicle is travelling and, of course, there are many spoken instructions such as "Air conditioner on/off", "Radio on/off", "Channel 3" etc., which are used regardless of vehicle's travelling conditions.
Furthermore, from the standpoint of improvement in recognition performance, it is desirable to reduce the number of spoken instructions.
A more detailed description of a typical speech recognizer will be made with reference to the attached drawing in conjunction with the present invention under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.